In recent years, micro-electro-mechanical system (MEMS) devices have been used to create compact scanning beam imaging systems. MEMS based scanning beam systems have been used extensively in various applications such as head-mounted see through displays, barcode scanners, endoscopes, and in portable projectors. Typically, two dimensional (2D) MEMS scanning beam systems (MEMS scanners) use a single mirror suspended in a gimbaled frame. These scanning mirrors are actuated by electrostatic or electromagnetic forces to reflect incident light beam from a laser source in order to project 2D image patterns onto a surface.
There are several drawbacks to conventional circuit architectures for driving MEMS scanning mirrors. Typically, currents with sinusoidal waveforms are employed to actuate (i.e. drive) MEMS scanning mirrors. However, this approach is not optimal as MEMS scanning mirrors driven by currents having sinusoidal waveforms suffer from discontinuities (i.e. dead zones) when the MEMS scanning mirrors are at resonance. This is undesirable as dead zones prevent data from being encoded onto, or decoded from, the projected beam. Further, MEMS scanning mirrors are highly reliant on a stable supply voltage in order to function optimally. If the supply voltage (from a battery cell for example) varies over time, the device would need to be recalibrated frequently. This translates to additional costs and operational inefficiency of conventional MEMS scanners.
Accordingly, what is needed is a robust and efficient means to actuate MEMS scanning mirrors. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.